Re: What time is it, really?
On Thu, Aug 09, 2018 at 04:15:36PM +0100, Darac Marjal wrote:
> Additionally, from http://doc.ntp.org/current-stable/ntpq.html#rv (rv allows
> one to read the offset for a particular association directly), "Note that
> time values are represented in milliseconds and frequency values in
> parts-per-million (PPM)."
Where do I even start....
OK, let's start with "man ntpq". The -p option says, "Print a list of
the peers known to the server as well as a summary of their state. This is
equivalent to the peers interactive command."
Not very useful. OK, the man page also says, "SEE ALSO
/usr/share/doc/ntp-doc/html/ntpq.html for the full documentation."
Of course, that file does not exist.
One might try to jump through hoops to try to find out how to obtain
this file, etc. I'll just assume for the moment that the end result
of those hoops would lead me to a page that's basically the same as
your URL shown above, so I'll skip those hoops.
Now, let's look at the URL you provided.
The #rv anchor points to a section for the "rv" command, which it seems
is an alias for the "readvar" command. There's no indication that this
is relevant to me in any way.
Right above that, is the peers command. The man page says that -p is
equivalent to peers, so we have an indication that the peers section of
this page might be relevant! OK! So, we read the "peers" section, and
it says, "offset of server relative to this host".
That's it. No units are mentioned in the output or in the documentation.
If we jump to the end of the page, there's just some tables and stuff.
Nothing comprehensible. If we jump to the start, and skip the
paragraphs of incomprehensible jargon, there's a sentence that says,
"For examples and usage, see the NTP Debugging Techniques page."
OK, so let's follow that link.
Under "Verifying Correct Operation", it says "The ntpq commands pe, as
and rv are normally sufficient to verify correct operation ...".
What's pe? Is that short for "peers"? Let's assume it's short for
"peers", and that whoever wrote this document wasn't writing it for
ordinary humans.
"The pe command displays a list showing the DNS name or IP address for
each association along with selected status and statistics variables."
Then it goes on to talk about the "as" and "rv" commands, which includes
some wording about times being in milliseconds, but why would I read that
paragraph at all? It's talking about these other two commands that I'm
not using.
...
So, since all of this documentation is not very user-friendly, I
rely on word of mouth to tell people, "Hey, see this offset field?
It's milliseconds, not seconds."
Reply to: